Before the Flood, people were living hundreds of years. As man grew more evil, God declared that man's lifespan would be reduced to 120 years. Modern biology has learned that we do indeed have built-in timers in each of our cells that limit the number of times they can divide. When enough cells can no longer divide, we die. We can even do things to speed up the timers.
The timers are called telomeres. However, every time a cell divides, a small part of each telomere is lost. When these telomeres are worn down to nothing, the cell no longer divides and soon dies. Researchers studied 58 healthy women between the ages of 20 and 50. All the women had children, but 39 of them had a child that was seriously chronically ill. Stress levels were measured through questionnaires while blood samples provided information about their cell health. Among other things, scientists checked for levels of an enzyme that maintains the health of telomeres. The mothers who saw their stress levels as high proved to have much shorter telomeres than those who reported little stress. They reported that cells from stressed women had telomeres that were as short as unstressed women ten years older.
Scripture tells us to cast all our cares on the Lord. Among the many blessings of doing so are healthy telomeres. Now we know how the Lord changed the lifespan of mankind. See Genesis 6:3!
Notes: Science News, 12/4: 2004, p. 355, C. Brownlee, "Stressed to Death